Loud neighbors and they vary on till pass midnight

I have lived in my apartment for two years and just recently my neighbors have started partying all through the night, pass midnight on the porch we both share, and I can hear them clearly through my window, with the ac running and all. I have told them about it, and how it is also waking my baby up who sleeps in my room, they stop for a couple of days but starts up again this time just no music, but same laughing, screaming and talking really loud. What should I do at this point?